In the processing of edible food products, and prior to final packaging of the products in small quantities for consumer use, it is often necessary to store large quantities of the material in bulk form and to do so under aseptic conditions in order to ensure the ultimate purity of the food product as applied to the consumer. It is often necessary that the materials remain in storage tanks for extended periods of time, often exceeding three or more months. Accordingly, it is important to avoid the introduction of any microorganisms into storage tanks for such products as microorganism contaminants, even if admitted into the tank in only small quantities, will eventually contaminate the entire storage tank contents. Additionally, depending on the type of food product which is stored, it is often necessary to maintain the stored material at a constant temperature. For example, when the food product has been previously partially or fully processed to a desired intermediate or final condition, for example the food product has been pasteurized and a change of its temperature during storage will adversely affect the condition, it is important that the aseptic storage facility does not adversely affect the food product temperature.
Various methods and apparatus have been specially designed for facilitating aseptic storage of bulk quantities of sterile products such as edible food products. For example, the Rechsteiner et al U.S. Pat. Nos. 3,951,184, 3,998,589 and 4,047,547 disclose methods and apparatus for sealing, sampling and filling aseptic storage tanks. The Nelson U.S. Pat. No. 3,678,955 further discloses an aseptic storage and valving system for facilitating storage of edible bulk materials. The Rechsteiner et al U.S. Pat. Nos. 3,871,824; 3,918,678 and 3,918,942 also disclose aseptic valves and filters for use in connection with bulk storage containers for aseptically maintaining edible food products.
Because packaging facilities for bulk food products are often remote from the storage locations for bulk food products, it is often necessary to transport the food products over extended distances to one or more packaging facilities. Road, rail and/or marine transport may be necessary. For aseptic products, it has been difficult in the past to maintain aseptic conditions of the bulk quantities of food products during transport over extended distances owing to the difficulties of preventing microorganism contamination and the cost of providing necessary equipment to reduce the likelihood of such contamination. For example, in the past, bulk quantities of tomato products have been shipped via railroad car. However, the railroad cars required outfitting with an expensive external nitrogen supply device to maintain a positive nitrogen pressure in each railroad car at a level of approximately 1-2 psig. Additionally, the railroad cars were subjected to steam sterilization prior to introduction of the tomato products to prevent microorganism contamination therein. Accordingly, the prior systems were limited to products which did not have significant temperature sensitivity. On the other hand, edible food products such as citrus products, which generally require low storage temperatures to avoid the requirement for one or more repeated pasteurization processing steps, were not suitable for transport under these prior rail transport systems.
Accordingly, a need exists for improved and economical methods and apparatus for aseptically transporting bulk quantities of sterile products such as edible food products.